Northern cod appear to be in better shape than any time since Ottawa imposed a moratorium on the Newfoundland and Labrador fishery two decades ago, a leading fisheries scientist says.

But George Rose, a former federal fisheries scientist who has studied cod stocks for decades, says the improvement is not nearly strong enough or well documented to warrant an increase in cod quotas.

"I haven't seen that amount of fish or the size of the fish that we encountered this spring in, well, it's over 20 years," said Rose, director of the Centre for Fisheries Ecosystem Research at Memorial University.

"We really are at a new beginning, particularly with regards to caplin and the cod, which seem to be on the increase — at least in some areas," he told CBC News.

Rose said researchers, though, will not have hard numbers on cod stocks until next spring.

Without enough data, he warns against increasing quotas for a commercial cod fishery.

There are limited fisheries for cod around Newfoundland and Labrador, although it represents a tiny fraction of the overall seafood industry.

In 2011, cod had a landed value of just over $11 million, with fishermen pulling in 9,745 tonnes.

Nonetheless, Rose said there are clear signals that cod are in better health than in many years.

"We've seen considerable and significant changes to the better, particularly in the northern regions — that is from the Grand Banks north up to Labrador, particularly in the one area we call the Bonavista corridor, where the fish have increased in number and in size rather dramatically in the last few years," he said.